Extensible scaffold



June 10, 1952 w H BREWSTER 2,600,199

EXTENSIBLE SCAF'FOLD 1 m 3 m NH S H m NR \N m Q mu S N .r 2 QR 3 Nu m au n \w m Q u 8 m8 3 Filed March 6, 1948 v Zhwentor muster- Will/21m H. B

J1me 1952 w. H. BREWSTER EXTENSIBLE SCAFFOLD Filed March 6, 1948 2SHEETSSHEET 2 Bnventor Will/km b. Brew-fer Patented June 10, 1952 UNITEDSTATES PATENT OFFICE 1 Claim. 1

This invention relates to a scaffold and it is one object of theinvention to provide a scaffold adapted to be suspended from an overheadsupport and of such construction that it may be adjusted longitudinallyand thus provide a scaffold of various lengths.

Another object of the invention. is to provide a scaffold having anextensible platform mounted in a frame which consists of end walls andfront and rear side walls, the side walls having upper and lower bars oftelescoping construction so that extension of the scaffold will bepermitted without weakening the scaffold.

Another object of the invention is to provide a scaffold having its sidewalls reinforced by braces which are longitudinally extensible andpivotally mounted at their ends so that they may extend diagonally andvary their angles as the scaffold is extended and contracted.

Another object of the invention is to provide a scaffold suspended froman overhead support by cables which are wound upon power-driven drumsmounted under the platform of the scaffold, the cables being extendedupwardly through guides mounted vertically at ends of the platform.

Another object of the invention is to provide a scaffold having a framewhich may be formed of pipes coupled to each other, certain of the pipesforming standards mounted vertically at corners of the scaffold andprovided with castors at their lower ends so that the scaffold may beeasily rolled along the ground from one place to another.

The invention is illustrated in the accompanying drawings wherein:

Fig. 1 is a view looking at the lower side of the improved scaffold.

Fig. 2 is a top plan view of the scaffold.

Fig. 3 is a sectional view taken transversely through the scaffold alongthe line 33 of Figure 1.

Fig. 4 is a vertical sectional view taken longitudinally through one endportion of the scaffold along the line 4-4 of Figure 3.

This improved scaffold has a platform I formed of a plurality of strips2 and 3 disposed in side by side relation to each other and slidablelongitudinally relative to each other so that the platform may beextended longitudinally when length of the scaffold is to be varied. Theplatform is mounted upon cross bars 4 which extend across the scaffoldand "are carried by side bars 5 formed of pipe sections 6 and I, thepipes 6 being welded at their outer ends to vertically extending 2corner posts 8 and 9 located at front and rear corners of the scaffoldand the front posts having upper portions bent to'form bars I llconstituting upper rails or bars of end wall of the scaffold. Outer endsof the strips 3 are firmly secured to the cross bars 4 upon which theyrest by bolts ll but the strips 2 and inner ends of the strips 3 arefree from the cross bars upon which they rest so thatthe strips 3 mayslide longitudinally along the strips 2 and thus allow the platform tobe longitudinally adjusted. The rear corner posts have upper endsconnected with each other by an extensible bar 12 consituting a top railfor the rear wall of the scaffold and the front corner posts areconnected with each other by an extensible bar l3 constituting a toprail for the front Wall which is of less height than the rear wall, andreferring to Figure 3 it will be seen that the top rail or bar I2consists of telescoping pipe sections I2 and [2 and that similartelescoping pipe sections i3 and l3 form the rail or bar I 3. At thelevel of the platform the front posts are connected with the rear postsby tubular bars l4 welded at their ends to the posts. It will thus beseen that the scaffold has a frame formed of pipes or tubes so connectedwith each other that the frame will be very strong and may be adjustedlongitudinally on the scaffold to increase its length when so desired.Castors l5 at lower ends of the corner posts allow the scaffold to beeasily rolled along the ground from one place to another. Guards [6 andI! are provided for the side walls and consist of telescoping pipesections or tubes having outer ends pivoted to collars I8 secured aboutthe corner posts and their inner ends pivoted to collars l 9 securedabout the inner tubes 7 of the side bars 5 between inner ends of theouter tubes 6 thereof. Since these guards are pivoted at their ends theymay tilt as the frame for the scaffold is extended or retracted andassume straight line positions between the corner posts and centers ofthe side bars 5. In order to prevent tools from slipping off of thescaffold along front and rear sides thereof there have been providedsheets of wire screening 20 which extend vertically between the sidebars 5 and the upper rails of the side walls in side by side relation toeach other and are secured by collars 2|. Similar sheets of screening 20are provided for end walls of the scaffold. The guards I6 and I! serveto prevent a workman from passing under the bars l2 and I3 if he shouldslip and roll or slide along the platform of the scaffold, thus reducinglikelihood of a 3 workman falling from the scafiold. The guards l6 andI1 also serve as shields for the screens of the front and rear sidewalls and reduce likelihood of them being torn or accidentally knockedloose during use of the scafiold.

In order to suspend the scaffold in position for use there have beenprovided cables 22 which are wound upon drums 23 suspended from plates24 mounted under the platform between certain of the cross bars '4. Theplates also carry motors 25 for rotating the drums and by properoperation of the motors the drums may be selectively turned indirections to wind the cables thereon for raising the scaifold or tounwind the cables and lower the scaffold. The cables extend from thedrums towards ends of the scaffold and have engagement with rollers 26carried by brackets 21 which project inwardly from the cross bars l4.After the cables have been engaged with the rollers they are extendedupwardly and through bushings 28 mounted vertically atupper ends ofcable guides 29 which extend transverse- 1y of the scaffold and are ofinverted V-shape formation and formed of angle metal bars having theirupper ends welded together and their lower ends welded to ends of theside bars '5.

Having thus described the invention, what is claimed is:

A scaffold comprising an elongated horizontal frame having front andrear side bars and vertical front and rear corner posts and end barsextending between and rigidly secured to the front and rear cornerposts, a rear rail extending between upper portions of the rear posts, afront rail extending between upper portions of the front posts, the sidebars and the rails forming front and rear framing, said rails beingformed of telescoping tubes having outer ends rigidly secured to theposts, said side bars being formed of tubular'end sections having outerends rigidly secured to the posts and an intermediate section extendingbetween and slidably mounted in the end sections, a platform in saidframe extensible longitudinally with the frame, diagonal bars connectingupper ends of the front and rear posts and together therewith formingend framing for the scafiold, guards for the scaffold consisting ofcollars carried by upper portions of said posts and by the intermediatesections of the side bars and diagonally disposed telescoping barspivoted at their outer ends to the collars of the posts and at theirinner ends being pivoted to the collars of the intermediate sections ofthe side bars, and screens extending vertically between the side barsand the said rails against outer surfaces thereof in side by siderelation to each other with the guards extending diagonally across themand constituting reinforcements for the screens.

WILLIAM H. BREWSTER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Great Britain 1.91 1

